Almost Ultimate Bookshelf Speakers 4" (passive)

thingiverse

*note: Added a new smaller volume box that's .14ft^3. It also has a neat "wood" surface texture. After testing, I didn't notice any difference between the old larger box and this. The larger box was just wasted space and filament. I also don't notice any difference with no polyfill filling at all; so I provided new tops with no basket.* After printing and listening to guppyk2's 4" back horn speaker enclosure, which left me wondering why his design is so popular, I was thinking that a traditional sealed box might do better. I noticed with the back horn design, it was really good at projecting the mid-range frequencies, but it left much to be desired in the area of bass. Also, I'm using these Infinity Reference speakers - (REF-4032CFX) which are a 2-way design. I don't believe a 2-way speaker is a good design for the back horn box because the separate tweeter does not get any benefit from the horn, making the speaker out of balance. I designed this box, which has .18 cubic feet of volume for 3" Dayton Audo speakers I have. Dayton provides all of the T/S parameters for that speaker, so the box design was easy. But sadly, Harman, the owners of the Infinity brand, don't have any of this info for their reference speaker. Infinity isn't the same brand I knew as a kid... Anyhow, they did say their speaker is designed to work in many enclosures because it is a car speaker, but will perform better in a sealed box, and they were right... I guess. Since I already designed a box for the 3" speaker, I decided to make a front cover that removed the port and took a 4" speaker. This is what we have here - a sealed box for a 4" speaker that is adapted from my 3" box design. BTW, that 3" box paired with the Dayton Speaker its designed for absolutely outperforms this 4" adaptation in terms of pure sound quality. Goes to show how driver size has very little impact on sound quality. My design has a "basket" behind where the speaker is mounted so that the polyfill stuffing does not touch the cone of the speaker. I provided a STEP file so you can change the design to work with your speaker. Also, experiment with the stuffing. It may actually hurt and not help. I am very impressed at how these speakers are now performing. The frequency range of the speaker is superior to the Horn box design and makes for a much better listening experience. The bass is stronger and the sound is more rounded out. Simply putting speakers into a random box doesn't ensure it will sound good. But chances are that speakers in this size will work well in this box, especially if its a car speaker. If you choose to use different speakers, you will need to design a mounting plate (or adapter) for your speakers bolt pattern. The ones I included are for the infinity speaker. Or, of course, you could just edit the step file and put in whatever mounting pattern you need. Ingredients (per speaker): 1x REF-4032CFX 1x Push in Type Right Angel Stereo Speaker Terminal Speaker wire Polyfill stuffing - optional and not recommended. Try no stuffing first. 2x 3mm screws to hold the terminal in 4x screws to hold the speaker in Glue Adhesive rubber feet You will need an amp to run these. I recommend Fosi Audio. https://www.amazon.com/gp/product/B07B8TKWS1/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1 https://www.amazon.com/gp/product/B06XK7GZ17/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1 Use your favorite glue to assemble. I use clear Gorilla Glue. Other notes: While a traditional sealed box might not be as exciting as a transmission line or back loaded horn design, there is no denying that the sealed designed is going to have a better chance at working well than something more fancy! In my experience, the back loaded horn designs found on Thingiverse just dont sound all that great.